The common input device of a computer system includes for example a mouse, a keyboard, a trackball or a touchpad. Among these input devices, the mouse is the most prevailing because it is very easy-to-use. When a mouse is held by the palm of a user's hand, the user may move the mouse to control movement of the cursor shown on the computer monitor.
FIG. 1 is a schematic view illustrating the connection between a conventional mouse and a computer system. As shown in FIG. 1, the computer system 2 comprises a computer host 21 and a computer monitor 22. The computer host 21 is in communication with a wheel mouse 1 and the computer monitor 22. The computer host 21 has a connecting port 211. The connecting port 211 is connected with the wheel mouse 1. A graphic-based window 221 and a cursor 222 are displayed on the computer monitor 22. The wheel mouse 1 is used for controlling the cursor 222 to have the computer host 21 execute a corresponding command. The wheel mouse 1 comprises a casing 10, a left button 11, a right button 12 and a scroll wheel 13. The casing 10 is used for supporting a user's palm P. When the casing 10 is moved by the user to result in a displacement amount, the cursor 222 shown on the computer monitor 22 is correspondingly moved by the computer host 21 according to the displacement amount. By clicking the left button 11 or the right button 12, a control signal is issued to the computer host 21. In response to the control signal, the computer host 21 executes a corresponding command. The scroll wheel 13 is arranged between the left button 11 and the right button 12. By rotating the scroll wheel 13, a scrolling signal is generated. In response to the scrolling signal, the computer host 21 executes a function of scrolling the graphic-based window 221.
FIG. 2 schematically illustrates a conventional wheel mouse to be manipulated by a user. For operating the wheel mouse 1, the user's palm P should be supported on the casing 10 while a first finger F1 is placed on the left button 11 and a second finger F2 is placed on the right button 12. In such way, the user may start to manipulate the wheel mouse 1. Moreover, during operations of the mouse 1, the mouse 1 should be placed on a flat working surface. Consequently, the cursor 222 shown on the computer monitor 22 is correspondingly moved according to the displacement amount of moving the mouse 1.
The conventional mouse 1, however, still has some drawbacks. For example, the mouse 1 should be handheld in the hand gesture as shown in FIG. 2, and the mouse 1 should be placed on a flat working surface during operations. This hand gesture makes the user's wrist in a floating state. If the mouse 1 has been used for a long term, the user may readily feel tired or uncomfortable because of wrist fatigue or wrist muscle injury. Moreover, if the working surface is uneven or the texture of the working surface is not obvious, the cursor 222 fails to be smoothly moved as the movement of the mouse 1. Therefore, there is a need of providing an improved mouse for reducing the fatigue of the user's wrist without the need of being moved on the flat working surface.